The cell culture core will provide cell culture support for this Program Project. The assays we use can detect hematopoietic progenitors at various stages of differentiation and can distinguish between normal and leukemic colony-forming cells. These assays are well suited to address a major issue arising in this Program Project, namely the derivation of the cells responding to various anti-leukemic agents investigated in this PO-1 whether they arise from the normal vs. the leukemic clones. We will provide cell culture support to Project 0023 by investigating the activity of novel kinase inhibitors on bcr-abl-dependent and -independent cell lines and on blood and marrow cells of both patients sensitive and resistant to imatinib mesylate (IM). Also, we will provide support to Project 0024 in studying the effects of lipocalin and antisense 24p3 and BCR on Ph+ cell lines and on normal and bcr-abl+ early and mature progenitors. In collaboration with Project 0020 we will study the effect of IM in combination with interferon and granulocyte-macrophage colony-stimulating factor prior to and during treatment with these agents to determine if these drugs change the ration between early and mature normal and leukemic progenitors.